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Watch your code run line by line — see arrays, linked lists, trees, graphs, recursion, and memory animate as each statement executes. A free Python Tutor alternative for 8 languages, right in your browser.
Most online compilers only print output. These do more: press Visualize and the compiler replays your program one line at a time, drawing every data structure as it changes and highlighting each variable read and write. It's the fastest way to see how sorting, binary search, recursion, and BFS/DFS actually work — and to debug why your algorithm does what it does.
Each language opens its online compiler with the built-in visualizer.
Python
names → objects memory
Step through Python while lists, dicts, sets, heaps, trees, and graphs animate — plus a Python Tutor–style view of names pointing to objects.
Java
arrays · collections · trees
Visualize arrays, 2D arrays, lists, maps, trees, and graphs, with recursion shown on the call stack as methods enter and return.
C++
STL + stack/heap memory
Watch STL containers, 2D arrays, trees, and graphs update, with a real memory view of stack frames, heap, and pointer arrows.
C
pointers · call stack
See arrays, strings, matrices, linked lists, and trees, with pointers and the call stack made visible — and even pthreads concurrency.
Go
slices + escape analysis
Visualize slices, maps, structs, trees, and graphs, plus a memory tab showing real escape analysis and slice backing-array aliasing.
Rust
ownership · Rc/RefCell
Step through vectors, trees, and graphs while ownership, borrows, Rc/RefCell sharing, and drop order become visible.
C#
List/Dict + threads
Visualize List, Dictionary, HashSet, Stack, Queue, 2D arrays, and trees, with recursion and threads/locks shown step by step.
Lua
tables · call stack
Watch tables render as arrays, 2D grids, and maps — plus linked lists, trees, and graphs — with reads highlighted on each line.
The same data structures and algorithms across every language.
1D arrays and 2D grids with each read and write highlighted — perfect for sorting and dynamic programming.
Nodes and pointers drawn as a diagram that rewires itself as you insert, delete, and traverse.
Vertices and edges laid out visually so you can follow breadth-first and depth-first traversals node by node.
Each call pushes a frame and each return pops one, so recursion and backtracking are easy to follow.
Dictionaries, sets, stacks, and queues update live as keys are added, looked up, and removed.
For C, C++, Go, and Python — real stack frames, heap allocations, and pointer/reference arrows.
Start from an example or type your own program in any of the 8 supported languages.
Run in step mode instead of plain output — the compiler records every line as it executes.
Move next and previous to watch data structures, memory, and the call stack update at each line.
A free browser-based tool that runs your code line by line and animates what happens in memory — arrays, linked lists, trees, graphs, hash maps, recursion, and the call stack update visually as each statement executes. It works for 8 languages with no installation or signup.
Yes. Like Python Tutor, it steps through your code and shows variables, references, and data structures as they change — but it supports 8 languages (not just Python), animates linked lists, trees, and graphs, and shows a real memory view with stack frames and heap for C, C++, Go, and Python.
Python, Java, C, C++, Go, Rust, Lua, and C#. Each has a dedicated online compiler with a built-in Visualize button.
Arrays and 2D matrices, strings, linked lists, trees, graphs, hash maps, sets, stacks, and queues — covering sorting, binary search, two-pointer techniques, recursion, BFS/DFS, and linked-list operations, each shown step by step.
Yes for C, C++, Go, and Python. The memory view shows stack frames, heap allocations, and pointer or reference arrows using real execution data.
Completely free with no signup. Every language visualizer runs in your browser.